Apparatus for moulding concrete pipes having a circumferential recess in the outer spigot end surface



S ept. 19, 1967 J. HESSELHOLT 3,341,910

APPARATUS FOR MOULDING CONCRETE PIPES HAVING A CIRCUMFERENTIAL RECESS INTHE OUTER SPIGOT END SURFACE Filed Nov. 2, 1964 INVENTORengHes'scllzol-f- Wm Am MA, mw

ATTORNEKS United States Patent 3,341,910 APPARATUS FOR MOULDING CONCRETEPIPES HAVING A CIRCUMFERENTIAL RECESS IN THE GUTER SPKGOT END SURFACEJens Hesseiholt, Brondersiev, Denmark, assignor to PedershaabMaskinfabrik A/ S, Bronderslev, Denmark, a company of Denmark Filed Nov.2, 1964, Ser. No. 408,113 Claims priority, application Denmark, Nov. 7,1963, 5,224/63 3 Claims. (Ci. 25-39) In some types of concrete pipes thespigot end shall be formed in its outer surface with a circumferentialchannel or recess which serves for accommodating and guiding a sealingring to fill and seal the play between the spigot end of the pipe andthe inner surface of the socket end, or the end corresponding thereto,of the adjoining pipe when the pipes are assembled to form a continuousstring.

As long as pipes have been moulded with the socket end pointing upwardlyin pipe moulding machines having a vibrating core, the provision of suchchannel or recess has not involved greater problems because the profilering serving to form said channel or recess could be placed and retainedinside the bottom ring which during the moulding process closes thelower end of the space or cavity between the outer mould and the coreand moreover constitutes the outer boundary surface of the extremeportion of the spigot end of the pipe, and finally serves for supportingthe moulded pipe during the subsequent setting after removal from themould.

When the setting of the pipe has finished, the bottom ring can beremoved and the inlaid profile ring, which is split at a point of itscircumference, can be withdrawn over the end of the pipe.

Now that it has been found most expedient, in the type of concrete pipemachines described, to mould concrete pipes with the socket end down, agreat problem has arisen as to the formation of the channel or recess inthe tip-turned spigot end of the pipe due to the fact that said spigotend is finished by means of a pressure cover being introduced into thecavity between the core and the outer mould for exerting a downwardlydirected pressure on the moulding mass therein and at the same time, onbeing rotated, smoothing the spigot end face of the pipe. It is directlycomprehensible that a profile ring laid into the concrete mass which issoft and plastic at this stage of the process, will not be retained inits proper position during the pressing and smoothing operations withoutbeing secured some way or other inside the pressure cover, and will notremain in such position after it has been released from the pressurecover in order to allow the latter of being withdrawn from the pipe.Also when the profile ring has been completely released from its rigidconnection with the pressure cover, the friction between the profilering and the pressure cover and between the latter and the concrete masswill involve a great risk of the profile ring being moved along upwardlyduring the withdrawal of the pressure cover and possibly tearing off theedge of the concrete pipe lying over said recess.

These drawbacks can be eliminated by use of the apparatus of the presentinvention as defined in the appending claims. An embodiment of thisapparatus is illustrated in the accompanying drawing, in which FIG. 1shows two interlocked annular members forming the pressure cover andguiding and retaining the inlaid profile ring during the first stage ofthe moulding of the spigot end of a concrete pipe,

3,34L9lil Patented Sept. 19, 1%6'? FIG. 2 a following stage where thelocking is released, and the outer annular member is being raised,whilst the inner annular member operates as a guide and abutment for theinlaid profile ring, and

FIG. 3 the two annular members locked together in another positionduring the final stage and ready for being raised clear of the concretepipe.

1 is a hub ring which, on being actuated from a hydraulic cylinder, notshown, is capable of transferring vertical forces through a link system2 to a pressure cover consisting of an outer annular member 3 and aninner annular member 4 and guiding and retaining a loose split profilering 5 of plastic or another suitable material. A splined shaft 6carrying the inner annular member 4 forms a guide for the hub ring 1which can be displaced along the shaft 6 between two positions in whichit can be locked by means of a locking pin 7 whereby the members 3 and 4are at the same time locked with respect to one another via the linksystem 2.

Bythe use of this apparatus, the spigot end of the pipe being mouldedcan be shaped and smoothed by means of the pressure cover having its twomembers 3 and 4 locked in such position (FIG. 1) with respect to oneanother as to permit, during the first stage of the moulding of thespigot end, the inlaid profile ring 5 which exerts a pressure againstthe outer member 3 of the pressure cover and is retained by friction, ofshaping the channel or recess without being displaced from its positionwith respect to the pressure cover, said ring being with the radiallyouter portion of its upper surface in engagernent with the inner memberof the pressure cover. In the second stage (FIG. 2) of the moulding ofthe spigot end, the two members 3 and 4 of the pressure cover arereleased from one another, and during the further pressing operation thelink system 2 connecting the two members of said cover causes the outermember 3 to be raised whilst the inner member 4 rmts on top of theconcrete mass and operates as an abutment for the inlaid profile ring 5so that its position in relation to the concrete pipe is not disturbed.In a third stage of the process (FIG. 3), the outer member 3- of thepressure cover is raised clear of the profile ring 5 and is in thisposition locked together with the inner member 4 of the pressure cover,in which mutual position said members can in conjunction be raised clearof the concrete pipe in the same manner as the heretofore known pressurecovers. The profile ring 5 can then be removed from the set concretepipe.

I claim:

1. An apparatus for molding concrete pipes having a circumferentialrecess in the outer spigot end surface, said apparatus comprising aprofile ring forming a core for said recess; outer and inner mold partsdefining between them an annular space; a pressure cover to close thespigot end of said space, said pressure cover comprising separate innerand outer annular members, said outer annular member completelysurrounding said ring and said inner annular member, and said innerannular member forming an abutment for said ring in the operative positions of said members; and means to displace said outer annular memberaxially with respect to said inner annular member, so that said outerannular member can be displaced from its operative position while saidinner annular member is retained in its operative position on theconcrete mass, said means being adapated to form a rigid connectionbetween said members for their simultaneous removal from between saidmold parts.

2. The apparatus of claim 1, wherein said means comprises a shaft, a hubring slidably mounted on said shaft,

4 v) a first set of links connecting said shaft to said inner ReferencesCited annular member, a second set of links connected to said UNITEDSTATES PATENTS first set of links and being pivotally connected at their(7 2,871,541 2/1959 James 249l44 X ends to said outer annular member andsaid hub rln 2,929,124 3/1960 James 249 10O respectively. 5

3. The apparatus of claim 2, further comprising means to lock said hubring with respect to said shaft to form SPENCER OVERHOLSER Puma);

said rigid connection between said members. E. MAR, Assistant Examiner.

1. AN APPARATUS FOR MOLDING CONCRETE PIPES HAVING A CIRCUMFERENTIALRECESS IN THE OUTER SPIGOT END SURFACE, SAID APPARATUS COMPRISING APROFILE RING FORMING A CORE FOR SAID RECESS; OUTER AND INNER MOLD PARTSDEFINING BETWEEN THEM AN ANNULAR SPACE; A PRESSURE COVER TO CLOSE THESPIGOT END OF SAID SPACE, SAID PRESSURE COVER COMPISING SEPARATE INNERAND OUTER ANNULAR MEMBERS, SAID OUTER ANNULAR MEMBER COMPLETELYSURROUNDING SAID RING AND SAID INNER ANNULAR MEMBER, AND SAID INNERANNULAR MEMBER FORMING AN ABUTMENT FOR SAID RING IN THE OPERATIVEPOSITIONS OF SAID MEMBERS; AND MEANS TO DISPLACE SAID OUTER ANNULARMEMBER AXIALLY WITH RESPECT TO SAID INNER ANNULAR MEMBER, SO THAT SAIDOUTER ANNULAR MEMBER CAN BE